Colombian President Andres Pastrana has inaugurated a new airborne, anti-guerrilla unit in the army's fight against rebel groups.

The Rapid Deployment Force - which is backed by helicopter gunships and transport planes - will be used alongside a new anti-narcotics battalion and a special river brigade.

Correspondents say the force is part of the government's twin-track approach to the guerrillas: on the one hand holding peace talks while at the same time boosting its military capability.

"Gone are the problems of moving support troops... The mission will be to hit strategic targets with all the force that these types of action demand," Mr Pastrana said at a ceremony at the Tolemaida military base in central Colombia.

Paratroops demonstrate rapid deployment

Until now the lack of air power and forward combat mobility has hampered the armed forces' efforts in the jungle war against the guerrillas, which has cost more than 35,000 lives in 10 years.

Mr Pastrana watched as hundreds of heavily-armed soldiers, their faces camouflaged with green and black war paint, parachuted from planes and roped down from helicopters.

The new force includes troops from three mobile counterinsurgency brigades, a US-trained special forces group and an artillery unit.

Mobile raids

It is backed by an array of aircraft, including 15 US-made Blackhawk helicopters, six Russian-built Mi-17 troop transport helicopters and two Hercules transport planes.

"The creation of the Rapid Deployment Force is an essential part of the effort to back the government in the search for peace," said army commander General Jorge Mora.

President Pastrana launched talks with the leftist Revolutionary Armed Forces of Colombia (FARC), in January, but there has been no let-up in the three-decade-old conflict.

FARC rebels control half of the country

Over the last three years the estimated 20,000 rebels, who control up to half the country, have struck a series of devastating blows against the 50,000-strong army

"The Rapid Deployment Force will carry out highly mobile counterinsurgency offensives on strategic targets to smash the subversives' will to fight," according to an army document outlining the aims of the new unit.

It said the force will attempt to increase the number of enemy casualties by "at least 50%".

As the unit began operations, the FARC said it was considering whether to observe a temporary ceasefire over the Christmas holiday period.

It had initially turned down a ceasefire call by Mr Pastrana last month.